Socket.IO Real-time Web Application Development Build modern real-time web applications powered by Socket.IO Rohit Rai BIRMINGHAM - MUMBAI Socket.IO Real-time Web Application Development Copyright © 2013 Packt Publishing All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews. Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book. Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information. First published: February 2013 Production Reference: 1120213 Published by Packt Publishing Ltd. Livery Place 35 Livery Street Birmingham B3 2PB, UK.. ISBN 978-1-78216-078-6 www.packtpub.com Cover Image by Suresh Mogre ([email protected]) Credits Author Project Coordinator Rohit Rai Esha Thakker Reviewers Proofreader Arnout Kazemier Elinor Perry Smith Andrew Keig Indexer Acquisition Editor Rekha Nair Wilson D'souza Graphics Commisioning Editor Valentina D'Silva Harsha Bharwani Production Coordinator Technical Editors Nilesh R. Mohite Ishita Malhi Dominic Pereira Cover Work Nilesh R. Mohite Copy Editors Aditya Nair Alfida Paiva Ruta Waghmare About the Author Rohit Rai is an accomplished software engineering professional and entrepreneur with several years of experience in developing products and consulting with clients on a variety of technologies, from enterprise applications on .NET and Java EE, consumer web applications focusing on JavaScript, data engineering and analytics platforms such as Pentaho and Hadoop, to modern platforms such as Groovy, Scala, and Node.js. He is a founder of TupleJump, a startup building a new-generation data engineering platform for unifying and optimizing the workflows of data scientists, engineers, and analysts, bringing in innovative data process development approaches and modern visualization frameworks, all built on cutting-edge technologies designed to scale transparently from a single machine to large, distributed big data clusters. He has previously worked with Cordys R&D, Pramati technologies, and various startups. He has consulted with clients like Intel and Sun, helping them develop products like Mash Maker and Zembly, powered by JavaScript. He was a member of one of the first teams on SocialTwist and developed one of the first widgets as a service platform and framework, which continues to power this widely-successful social media marketing and referral platform used by many Fortune 500 companies. In open source, Rohit is a core committer and the administrator of Matisse (http://www.matisse.org/), the collaborative design platform. He is also the creator of socket.io.play, the Socket.IO module for the Play framework, and various open source projects hosted at GitHub (https://github.com/rohit-tingendab). Acknowledgement Writing a book, especially your first one, is an uphill and demanding task that cannot be accomplished by a single person without support from several others, and this book is no different. I would like to thank everyone who has played a role in helping me write this book or helping me reach the point where I could think of writing my own book. Though I cannot mention all the people by name, I am heartily grateful and indebted to everyone. However, I would like to mention the people who have played a directly important role in this book. First of all, I have to thank my father and his elder brother, my uncle, who together, played the most important role in my personal and academic development. They inscribed on my mind, the importance of learning and knowledge above all else in life. I would like to thank my wife, Paridhi, and my brother, Rajat, for bearing with my tantrums and idiosyncrasies, and still understanding and supporting me during my long hours of work and writing. I couldn't have pulled it off without them. The other very important person that I need to mention is my cousin, Shiti, who was always reviewing the book, giving exceptional feedback, running, debugging, and correcting the code for me, and also taking over quite a bit of my workload and my projects whenever she could. I have to thanks all my friends and cousins who played an important role in my upbringing, and who understood my missing all their parties and celebrations all the time. I have to thank my friends, partners, and founders at my two ventures, Satyaprakash at TupleJump and Guillermo at Happymer, who have unconditionally supported me through the writing of this book and coped with me missing meetings and running slow at work from time to time. I thank Pramati Technologies, the place where I learned most of what I know today and spent most of my career. I thank Jay and Vijay Pullur for starting this wonderful company; it is one of the very best places to work at. I have to thank my managers, mentors, and guides at Pramati, specially Ramesh Loganathan, Chandrasekhar Sivaram, and KVP who have taught me a lot. All of them helped develop particular skill sets within me, without which I could never have written a book or started my own company. Chandru and KVP gave me the freedom to choose my projects, run my teams my way, and also the support to build Matisse and socket.io.play. Ramesh, who was the first published author I got to know in person, is my inspiration to write. Talking about mentors, I owe my professional success to Vivek Lakshman, my manager at Cordys and SocialTwist, my mentor, protector, guide, and above all, a friend I probably didn't do much to deserve. He has always challenged me to set higher goals for myself and then supported and pushed me to achieve these targets. The positive energy that he brings to any conversation helps boost the morale of everyone around. My thanks go to everyone at Pramati for helping me, assisting me, and guiding me from time to time. I must thank my friends and colleagues, Apurba and Sunny (now at Sprinklr), who have always challenged me to learn more, explore more, and keep improving from time to time. Sunny was the one who forced me to dig deeper in JavaScript and functional programming during our SocialTwist days. And Apurba is someone from whom I have learned a lot; I still feel like a student in his presence. The acknowledgements for a book on any technology would be incomplete without thanking the creators. I am thankful to Ryan Dahl, the creator of Node.js and Guillermo Rauch, the creator of socket.io, and the countless open source contributors to these and other enabling technologies, without whom these projects, and in turn this book, would have been impossible. Last but not the least, I have to thank the team of editors and reviewers for this book. I thank the editors at Packt, Manali, Harsha, and Esha, who have been very good to me, understood the challenges for a first-time writer, and been considerate with delays and shuffling of deadlines. I also thank the reviewers who have done an excellent job of pointing out what is missing in the book, correcting the mistakes, and reviewing the code. Thank you guys, you have been great! About the Reviewers Arnout Kazemier is a Software Engineer from the Netherlands. He was originally schooled as a multimedia designer, but quickly rolled in to the world of frontend development and started to appreciate the beauty of JavaScript. After finding out that it was also possible to write JavaScript on the server side, he started using Aptana Jaxer and Narwal in his spare time. It wasn't until much later that Arnout heard about Node.js and its possibilities, and decided to take it for a spin when version 0.1.3 was released. Since then, he has never looked back. When Arnout joined the first Node.js hackatron (Node Knockout 2010), he built a real-time heat mapping engine on Node. js using Socket.IO. During the programming contest he learned a lot about Socket. IO and solved tons of issues that he encountered during the development of his entry. When the contest ended, he didn't stop contributing to Socket.IO, eventually becoming the first core team member of Socket.IO. He has been talking at different tech conferences since. Fast forwarding to 2013, he now spends time working on his own startup website http://observe.it (it won Node Knockout 2011) which allows you to observe and learn from your user's behavior in real time. He's still actively involved with the development of Socket.IO and conducts research on the connectivity of the real-time web and the impact of firewalls & virus scanners. Andrew Keig has been building cutting-edge web applications for over 12 years. Andrew is a director at airasoul.net, which he runs with his artist wife Rima. Airasoul specializes in the design and build of scalable, RESTful, specification-driven, real-time web and mobile-based applications on both the Node.js and .NET stacks. Andrew has a degree in Computing, and blogs at blog.airasoul.net on topics he is passionate about, such as Node.js, REST, Web APIs and Behavior-Driven Development.